1. Field of the Invention
The present invention relates to a remote operation system for unlocking the doors of a vehicle.
2. Description of the Related Art
As shown in FIG. 4, a remote operation system according to the related art has a portable transmitter 1, and a receiver 3 and a moving mechanism 4 mounted on a vehicle 2. When an automatic operation mode button C of the transmitter 1 is pressed, a signal is periodically outputted from the transmitter 1. When the transmitter 1 enters an automatic operation mode region, the receiver 3 receives the signal, and then the doors of the vehicle 2 are unlocked. Further, when the transmitter 1 is moved outside the automatic operation mode region, the receiver 3 does not receive the signal periodically outputted from the transmitter 1, and thus the doors are locked.
Here, one or several signals to be transmitted first when the instruction button C is pressed have high output intensity. Accordingly, even when the instruction button C of the transmitter 1 is pressed at a position outside the automatic operation mode region, the signal to be transmitted first is received by the receiver 3, and thus the receiver 3 enters a state capable of receiving the automatic operation mode. Then, when the transmitted signal is not received by the receiver 3, the door lock operation is performed (for example, see JP-A-5-153664 (FIG. 1)).
Since the receiver does not have a function of discriminating the position of the transmitter, when the receiver receives the signal from the transmitter, all doors are unlocked. For this reason, the door of the vehicle on a side where a person is not riding is also unlocked, which causes a problem in security.